1. Field of the Invention
The invention is directed to an improved fuel delivery system for delivering fuel to an internal combustion engine of a motor vehicle.
2. Description of the Prior Art
A fuel delivery system with a pump chamber and a revolving impeller in the pump chamber rotating about a pump axis is already known from German Patent Disclosure DE 32 26 325 A1 in which protuberances are provided on predetermined end walls inside the pump chamber. The protuberances are disposed radially inward from a pump conduit provided in the end wall, and they extend away from the pump conduit in a straight line, rising in wedgelike fashion in the direction of revolution. In the rotation of the impeller in the pump chamber, the fluid backs up at the protuberances, generating a resultant force in the axial direction, pointing away from the end wall, and preventing the impeller from being able to come to rest on one of the end walls of the pump chamber. As a result, the protuberances act like a hydrodynamic bearing. Because of this, the friction acting counter to the impeller rotating in the pump chamber is reduced, and the efficiency of the fuel pump is increased. A disadvantage is that the protuberances are very complicated to produce.